Daniel Webster, the Director Johns Hopkins Center for Gun Policy and Research, did his homework, and the results confirm what our common sense would also tell us: If you repeal background checks, then criminals have an easier time acquiring guns... and have an easier time using them to kill people.

Normally it’s very hard to ascribe changes in homicide rates to any one particular factor, but Webster and his co-workers found strong evidence to support the idea that the repeal of the permit-to-purchase law was the cause. [...]

90 percent of states allow private sales to take place without background checks, suggesting that if Webster’s research is right, it’s possible that we might be able to reduce national homicides by nearly 25 percent if there were universal, federally mandated background checks. That would translate, given the 11,000 annual gun homicides in the United States, to 2,750 lives saved per year.

Why is this so difficult for people like the NRA's Wayne LaPierre to grasp? Oh wait. It isn't. They just don't care because profits and (rapidly diminishing) power are their priority, not saving lives.